JPS5849743B2 - Vibration absorption device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for reducing vibrations transmitted from a vibration generator to a support that supports the same, and is particularly suitable for application to vibration absorption for internal combustion engines.

Generally, when a part of a machine or mechanism moves, vibration is generated.

In particular, vibrations generated by the operation of an internal combustion engine spread discomfort and noise to the surrounding area, and various efforts have heretofore been made to reduce the vibrations.

Normally, such an internal combustion engine is installed on the ground, structure, etc.
It is installed on a mounting base 3 that is installed above and supports this internal combustion engine 2, and when this is expressed as a vibration system model, a mass point of weight M corresponding to the internal combustion engine 2 as shown in FIG. 4 and a spring 5 corresponding to the mounting base 3 which attempts to return it to a position of equilibrium.

By the way, internal combustion engines, especially diesel engines, generate large fluctuating loads due to inertia and explosive force.
This fluctuating force is constantly acting on the vibration system shown in Figure 1b, and this fluctuating force is transmitted to the foundation 1 depending on the characteristics of the vibration system, causing unpleasant vibrations and the like mentioned above. They often caused noise to those around them.

The purpose of the present invention is to provide a device that exhibits an excellent vibration absorbing effect particularly for such an internal combustion engine, and the structure of the vibration absorbing device of the present invention that achieves this purpose is designed to prevent sliding friction from occurring. One end of a plurality of leaf springs stacked one above the other is attached between the vibration generator and its support, and a weight of arbitrary weight is attached to the other end of the leaf spring so that the distance from the one end can be changed. It is characterized by its heavy weight.

In other words, the present invention, as shown in FIG. Attach one end of a plurality of leaf springs 14 stacked one on top of the other so that
is fixed.

If this is expressed as a vibration system model, as shown in FIG. 2b, the conventional vibration system shown in FIG.
, a controller 18 corresponding to the sliding friction of this leaf spring 14 is added.

By the way, the mass point 4 shown in FIG. 1b, that is, the internal combustion engine 2
The amplitude of (
On the other hand, the amplitude X of the mass point 19, that is, the vibration generator 11 in the case of the present invention shown in FIG.
K1 is the spring constant of the support body 13 that acts as the spring 20. k1 is the spring constant of the leaf spring 14. k1 is the mass of the weight 15 which is the haze distribution point 16. 01 The magnitude of the fluctuating load acting on the mass point 19 is F1 The angular frequency of the fluctuating load acting on the mass point 19 is ω, m/M is μ, fi7; is ωa (natural angular frequency), and 2m・Ωn is Cc (however, Ωn=JK/M
), ωa/Ωn is expressed as f, and ω/Ωn is expressed as g.

Therefore, the frequency of the fluctuating load acting on mass points 4 and 19 (corresponding to the rotation speed in an internal combustion engine) is plotted on the horizontal axis, and the frequency is calculated using equations (1) and (2) above. The correlation between the amplitudes X of mass points 4 and 19 on the vertical axis is shown in the graph of FIG. 3 ajb.

In the figure, the solid line represents the case according to the present invention, and the broken line represents the case shown in FIG.
This represents the case in which the vibration absorbing device of the present invention shown in FIG.

Note that Figure 3a shows the case where the resonance point is below this maximum frequency P, and Figure 3b shows the case where the resonance point is higher than the maximum frequency P, but it is clear from these graphs that As described above, in the present invention, the amplitude X can be significantly reduced regardless of the position of the resonance point.

Also, the shape of the solid line curve in these graphs is
The mass m1 of the weight 15, the spring constant k1 of the leaf spring 14, and the coefficient of friction C associated with the sliding friction can be changed arbitrarily by appropriately selecting the rotational speed of the internal combustion engine to maximize the vibration absorption effect. It is preferable to shift the position where the amplitude X is minimum on the graph to a range of .

Next, a specific example of the vibration absorbing device according to the present invention will be described in the fourth example.
As shown in the figure.

According to this, an internal combustion engine 21 and a mounting base 22 that supports it are fixed with bolts 23 and nuts 24, and one end of a plurality of leaf springs 25 stacked vertically is held between them, and the other end A plurality of weights 26 stacked one above the other are fixed with bolts 27 and nuts 28, and the mass is adjusted by the number of stacked weights 26.

The mounting position of the weight 26 to the leaf spring 25 is such that the weight mounting holes 29 through which the bolts 27 pass are spaced at regular intervals so that the weight 26 can be mounted at any position from one end to the other end of the leaf spring 25. A hole is provided in the leaf spring 25,
This makes it possible to change the spring constant of the leaf spring 25.

Further, the leaf springs 25 are connected to each other by bolts 3o1 nuts 31, and by adjusting the tightening force thereof, the friction coefficient of the sliding friction between the leaf springs 25 that occurs as the weight 26 moves up and down can be changed. Can be done.

As described above, although the vibration absorbing device of the present invention has an extremely simple structure and is inexpensive, it is capable of absorbing vibrations of a vibration generator to a large extent.

[Brief explanation of drawings]

Fig. 1a is a principle diagram showing the installation concept of an internal combustion engine, Fig. 1b is a principle diagram showing this as a vibration system model, and Fig. 2a is a principle diagram showing the installation concept of an internal combustion engine. Figure 2b is a principle diagram showing this as a vibration system model, and Figures 3a and b are vibration generation in the vibration system shown in Figure 1b and the vibration system shown in Figure 2b. This is a graph showing the relationship between the vibration frequency of the body and its amplitude, where the solid line is the one according to the present invention and the broken line is the one shown in FIG. 1b without the vibration absorbing device. Further, FIG. 4 is a cutaway view showing a part of an embodiment in which the vibration absorbing device of the present invention is applied to an internal combustion engine. In the drawing, 11 is a vibration generator, 13 is a support, 14 is a leaf spring, 15 is a weight, 21 is an internal combustion engine, 22 is a mounting base,
23, 27, and 30 are bolts, 24, 28, and 31 are nuts, 25 is a leaf spring, 26 is a weight, and 29 is a weight attachment hole.

Claims (1)

[Claims] 1 One end of a plurality of leaf springs stacked one above the other is attached between the vibration generator and its support to generate sliding friction, and the distance from the one end to the other end of this leaf spring is changed. A vibration absorbing device characterized by attaching a heavy pyramid of arbitrary weight.